Over the past several years concern over the physiological and biochemical effect of inhaled oxidants on the lung has increased rapidly. Two of the most dangerous oxidizing agents present in the urban environment are ozone and the oxides of nitrogen, especially nitrogen dioxide. Exposure to relatively high concentrations of NO2 or ozone produces serious and often fatal lung damage. Oxygen, clearly an oxidant agent in high concentrations, alters pulmonary structure and function after relatively short exposures in various mammalian species. We plan to develop an in vitro system (which is relevant to an in vivo situation) for assessing the toxicity of oxidant air pollutants and to utilize this system to learn more about the effects of air pollutants at the cellular and subcellular level. The L-2 rat lung cell strain will be used in the study. It retains differentiated characteristics possessed by the type II alveolar epithelial cells present in whole lung. Like their in vivo counterparts, L-2 cells synthesize a highly saturated lecithin which is the major component of environmental pollutants on surfactant production by type II alveolar epithelial cell in whole lung. To this end we will employ a range of assays to detect degrees of damage ranging from very subtle changes in cell function to outright cell death and determine the degree of toxicity of various doses of different pollutants and various oxygen concentrations. We will also investigate the feasibility of utilizing antioxidants as protection against the deleterious effects of those agents. A wide range of antioxidants will be tested including dl-a-tocphoperol.